The present invention concerns a trailer equipped with a main towing device, vertically movable with respect to the axle(s) of the trailer, and a centering device fastened underneath the front part of the trailer which projects over the roof of the motor vehicle.
A trailer of this type is already known under WIPO Patent Number WO 86/01780. It has in common with the present invention the fact that by means of an integral and vertically movable towing head, the trailer is connected to a hook device with a round head which constitutes a ball-type joint mounted at the back of a motor vehicle, and the fact that the front part of the trailer projects over the roof of the motor vehicle and is fastened to it at one point.
All currently known motor vehicle/trailer combinations have the disadvantage that hitching the trailer to the back of the motor vehicle is difficult. Fastening the trailer to the roof of the vehicle is also difficult, especially because of the lack of transverse and longitudinal clearance of the main towing head and because of the slide system used to fasten the trailer to the roof of the motor vehicle, which makes it necessary to couple the trailer to the roof of the motor vehicle first.
The present invention overcomes these disadvantages by using an articulated main towing device, fitted on the trailer, which is hooked to a conventional ball-type hitch situated at the back of the motor vehicle which can be used for all other conventional trailers, in conformity with international road regulations. This articulated main towing device and ball-type hitch allows rapid coupling and uncoupling of the trailer and motor vehicle in spite of the combined use of a flexible coupling device to fasten the front part of the trailer to the roof of the vehicle by means of a transverse and vertical centering device which slides from front to rear and is fitted on the trailer. Thus, it is possible to couple the centering device either before or after coupling the main towing device of the trailer to the back of the vehicle.
The main towing device is preferably situated in the vertical and longitudinal midplane of the trailer to which it is coupled, and its head is situated in front of its axle(s), and hooked to one of the conventional ball-type hitch devices that are commonly mounted on the back of motor vehicles.
The main towing device of a trailer embodying the present invention may include of the following elements:
1. A towing head in which the tow-ball of the motor vehicle is lodged, equipped with a handle system which allows coupling and uncoupling as the handle is pushed down or raised up respectively;
2. A body in which the piston fixed to the towing head can be lodged and which drives the overrunning brake system of the two or four wheels of the trailer;
3. One or two articulated arms that connect the body of the main towing device to a transverse rotating shaft, in one or two elements, situated rearward of the body, and enable the towing head to follow the upward or downward movement of the tow-ball mounted on the motor vehicle, which moves with the wheels of the axle(s) of the vehicle when they pass over relief variations with respect to the ground level supporting the wheels of the axle(s) of the trailer whose center of gravity is approximately situated in the transverse axis of the axles;
4. One or several compression and/or tension springs fastened at one end to the main towing device body or arms by means of bearing plates and at the other end to the chassis or body of the trailer, the possible action of the springs being intended to support and dampen the upward and downward movements of the towing head depending on the movements of the motor vehicle with respect to the trailer in the case of relief variations that place the wheels of the vehicle and trailer at a different ground level;
5. A sliding device for the pivoting shaft on which hinges the arm(s) of the main towing device body. The sliding device includes one or two elongated holes, or as an alternative, one or two slides with rollers, ball bearings, or plates or blocks made of metal or self-lubricating material sliding in rails, which enable the pivoting shaft of the towing head to shift from front to rear, and to the ends of which the bottom plates with rollers, plates or blocks are fastened. The shifting of the shaft induces shifting of the towing head both in the plane perpendicular to the axis of the axle(s) and slantwise, more to the front or to the rear on the right hand side or more to the front or to the rear on the left hand side. This forward/backward, left/right shifting device, together with the upward and downward movement of the articulated arm(s) of the towing body, makes it easy to couple the towing head onto the ball mounted on the motor vehicle, even if the head is not exactly placed in the vertical, horizontal, longitudinal or transverse plane with respect to the ball. The sliding and articulating of the main towing device makes it possible to move the towing head in all directions to couple it onto the ball, without shifting the motor vehicle or the trailer, whether the trailer is being supported by the roof of the vehicle or not;
6. A device which locks the pivoting shaft of the main towing device in a road-ready or working position, once the trailer and the motor vehicle have been realigned in the vertical midplane, by simply moving the vehicle forward for a few meters in a straight line, for example, once the trailer has been coupled to the back and roof of the vehicle. This locking device may consist of a screw mounted to a crossbar of the chassis, and a head which can easily be screwed down by means of a crank. For example, a screw equipped with a nut, mounted on a device fitted on the pivoting shaft of the towing device, is tightened through a yoke-type bar, firmly locking the pivoting shaft of the main towing device in the road-ready or working position, i.e. in backstop position, perpendicular to the longitudinal axis of the trailer, allowing upward or downward movement of the head described in C.
As an alternative, the sliding of the rotating shaft may be locked by means of transverse or vertical locks, pulled by one or several locking springs which lock the sliding of the rotating shaft in a road-ready or working position. The unlocking is performed by means of a pedal or handle; the locks are maintained in released position by a sliding or swinging wedge-type part actuated by a spring. When the plates or blocks with which the pivoting shaft of the towing device is connected come up against the slide stop on the rear safety ends that are solidly fixed to the rails, the wedge-type part is forced back by a metal or self-lubricating block, or the roller plate, fastened to one of the ends of the rotating shaft of the towing device, so that the wedge-type device is pushed out of the away, thus releasing the locks to be moved by the main locking spring(s) into the position that holds the sliding parts of the main towing device firmly against the rear slide stops.
The device which maintains the trailer in line with the motor vehicle, in order for the motor vehicle and trailer combination to manoeuvre and behave like a single vehicle, is mounted on the front of the trailer and on the roof of the motor vehicle, and includes the following elements:
1. A roof-rack reinforced with crossbars and struts which supports the front part of the trailer, and is solidly clamped to the roof of the motor vehicle;
2. Two high-strength sliding rails, carried by the roof-rack, each including an element which slides freely in a C-shaped rail. Self-lubricating rollers or ball bearings are linked by a bearing plate in which a hole has been pierced to receive the grooved centering head of the trailer. A key, composed of one or two elements which operate as a pliers while remaining an integral part of the plate, will fit into the grooved centering head, mounted underneath the front part of the trailer, thus interlocking the head with the roof-rack in vertical or transverse direction; and
3. A centering head, fixed to an element made of elastic material, commonly called a "silentbloc" is mounted on the reinforcing structure of the trailer's front part through a support which is also fixed to the "silentbloc". The "silentbloc" permits slantwise movements in all directions as well as the dampening of these movements with respect to the vertical axis of the centering head when the wheels of the trailer pass over bumps, or when in oblique position with respect to the ground level supporting the wheels of the motor vehicle. The oblique position occurs when the wheels pass over relief variations and when the trailer and the motor vehicle change position due to the independent action of their respective individual suspensions. The free end of the centering head may have a conical shape to make it easier to lodge in the hole in the bearing plate carried by the roof-rack mounted on the roof of the motor vehicle. The slantwise left/right and forward/backward movements with respect to the direction of motion are absorbed by the centering head. Movements of the trailer and the motor vehicle toward and away from each other are possible. These movements are caused at the fastening point of the trailer to the roof-rack of the vehicle by:
a. the upward and downward movement of the trailer with respect to the vehicle caused by the upward or downward shifting of the towing head of the trailer by means of the articulated arms of the towing device; and PA1 b. the forward/backward play of the brake piston fitted on the towing head, or by the forward or backward movement caused, before the head of the main towing device has been lodged on the tow ball, by a manipulation of the trailer or of the motor vehicle, once the centering head has been lodged in the bearing plate.
The movements described in the preceding section are made possible by the sliding of the bearing plate. This bearing plate, onto which is keyed the centering head fitted on the front part of the trailer, is connected with the sliding rails carried by the roof-rack, the roof-rack being solidly mounted on the roof of the motor vehicle. It is also possible to operate the sliding bearing plate forward or backward by hand, without having to shift the trailer or motor vehicle in order to exactly oppose the hole in the plate mounted onto the vehicle and the centering head of the trailer. This makes keying of the centering head, and consequently the coupling, easier.
As an alternative, the centering head, which is fitted on an element made of "silentbloc" is mounted on the front part of the trailer by means of a support fastened onto a slide, thus allowing it to slide from front to rear, absorbing the movements of the trailer and the motor vehicle toward and away from each other. The support of the centering head may be hand operated by means of a handle to make it slide from front to rear, thereby aligning the centering head with the hole in the bearing plate equipped with the key which, in this variant, is rigidly mounted on the roof-rack. It is thus not necessary to position the trailer, or the motor vehicle, with precision.
The trailer of the present invention, may be equipped with a hinged panel covering its entire rear face. When the trailer is not being driven, this panel may be used to create an awning, supported and kept in place by a minimum of two removable poles made of steel or aluminum tubes and adjustable in height. A system of elastic fastening lugs may be used to hang a fabric tent canopy underneath the lifted awning panel, the tent canopy of which is composed of three or four sides, mounted approximately vertically, ensuring tightness on the ground, and of one element assembled to the other elements to form a near horizontal covering. The advantages of a tent canopy system underneath the rear awning panel may be preserved even when the panel remains closed on the rear face of the trailer, by means of a minimum of three easily removable bars, fixed so as to form a framework on the hinge, level to each side of the rear face of the trailer and to the upper ends of the two poles that were initially intended to support the rear panel in lifted position, and fixed by way of crossbar between the upper ends of the poles. Suspending fastening lugs of different tent canopy sides from the bars may be performed by means of a system similar to the one used to fix the lugs underneath the lifted rear awning panel. The awning panel, hinged down, may be equipped on its upper outside part with fastening points underneath the hinge line, to replace the fastening points situated on the inside of the panel used when the latter is in lifted position.
When the trailer is uncoupled from the motor vehicle and the motor vehicle has been moved a few meters away, it is also possible to utilize the space situated underneath the front part of the trailer, by installing a tent canopy composed of several sides, whether liftable or not, the trailer being supported by hinged posts.
After the trailer has been uncoupled from the motor vehicle, the motor vehicle can make use of its ball-type towing device to tow any other conventional trailer. The roof-rack may remain mounted on the roof of the vehicle and be used in a conventional way to carry goods, and, after having been easily mounted on a vehicle roof with or without a gutter, it may be just as easily dismounted without leaving any apparent fixing marks.
Therefore, it is an object of the present invention to provide a combination motor vehicle and trailer which maintains alignment of the trailer and motor vehicle while driving.
Another object of the present invention is to provide a combination motor vehicle and trailer which allows separate use of the car once the trailer has been unhitched.
Yet another object of the present invention is to provide a highly maneuverable single body vehicle, such as a motorized camping vehicle.